Major depression is one of the most prevalent mental disorders to afflict adults. It seriously impacts role functioning and typically takes a recurrent course. Although antidepressant medications have proven efficacy and are the most common treatment for depression, up to 70% of adults do not complete the recommended regimen. There is also evidence that cognitive-behavioral therapy in conjunction with medications is more effective than medications alone in preventing depression relapse. This project will develop and evaluate an interactive multimedia intervention aimed at improving regimen adherence and preventing depression relapse for outpatients receiving antidepressants. Empirically validated frameworks will be adapted for self-administration via the Internet or CD/DVD-ROM. The intervention will consist of knowledge- and skills-based modules including: understanding depression, regimen adherence, mood monitoring, behavioral activation, cognitive restructuring, interpersonal relations, relaxation, and planning for the future. The competency-based instructional design will be structured for multiple sessions using video- based tutorials, testimonials, and behavior modeling vignettes. Additional browser modules will include depression self-screening, learning to relax, enhancing social skills, and improving communication and problem solving. The online support system will include an electronic bulletin board, personal weekly conferences with an intervention coach, and an ask-an-expert forum. A collaborative care tool will be developed to allow managed care staff to monitor their patients'progress with antidepressant treatment and engagement in the IMM program, as well as provide ongoing support. The intervention will include six target populations: men and women in early, mid and late life. The basic structure of the program will be the same for each target population, but specific content will be customized to each user group. The Phase I prototype, targeted to 18-39 year-old women, provided training on understanding depression, regimen adherence, mood monitoring, and behavioral activation. It was evaluated in a within-subjects design feasibility study. The results showed significant pre to post and pre to follow-up changes in depressive symptomatology, pleasant activity engagement, knowledge, perceived stigma, self-efficacy, and behavioral intentions to use the skills taught. Subjects found the program easy to use and gave it high satisfaction ratings. The fully developed Phase II product will be evaluated in a large randomized trial (N = 270) with a six- month follow-up period to compare change in depressive symptoms as well as depression remission and relapse rates between intervention and control conditions. Subjects will be managed care patients who are undergoing antidepressant treatment via primary care. Major depression has become a critical public health issue given its high prevalence and associated impairments. Although antidepressant medications have proven efficacy and are the most common treatment for depression, nonadherence to antidepressant therapy is a key variable associated with depression relapse and recurrence. Given the evidence that combining cognitive-behavioral therapy with medications is especially efficacious, there is a critical need to develop relapse prevention programs that emphasize antidepressant medication regimen adherence combined with cognitive-behavioral strategies that can be easily implemented and widely disseminated.